Solid drawings are made up partly of construction. Perspective and foreshortening help make the drawings even more convincing - and harder to do. They also afford you more creative choices to tell your stories with.
Note how Bugs' feet are in the same perspective (the same angle) as the grave pit.
Many characters in today's cartoons will be drawn in 3/4 angle, yet their feet are placed on a horizontal line that completely ignores the perspective or angle of the rest of the characters. It hurts my eyes to see that so much. It makes it look like the leg that is farther away from is is longer than the one that is close to us.
We are also looking down on Bugs so his head is much bigger than his feet and his body is foreshortened.
I love the hills and valleys in Bugs' ears. Very subtle and adds even more form.
The way Bugs drags Elmer floating through the air and into the grave is cheated. Even McKimson couldn't figure out how to make that look natural. I bet he was cursing Clampett for this scene. It's full of technical problems to solve - yet the result makes the cartoon even funnier. It's amazingly directed - as someone pointed out in the comments the other day, Elmer is crying to the music. As always, Clampett's actions and gags flow along melodic music like a cartoon ballet.
I can't imagine how they choreographed all these ideas and made them work together so smoothly - and funny. They must have been supermen in the 1940s.